Process of treating cellulose and cellulose-ester filaments and the product thereof



Ratentell July 23, 1929. e UNITED STATES HARRY r. nasss'r'r, or

PATENT OFFICE. i I

CYNTHIANA, KENTUCKY.

PROCESS OF TREATING CELLULOSE AND CELLULOSE-ESTEB- FILAMENTS AND THE PRODUCT No Drawing.

This. invention relates in part to the treatment of spun. artificial silk waste and particsired, toproduce permanently crinkledfilaments resembling wool therefrom. I

In the manufacture of artificial silk there is produced in commercial practice a considerable amount of cellulose or cellulose ester filaments which by reason of the presence of foreign materials therein or upon the surface thereof cannot be satisfactorily used. I

- have discovered that such artificial silk waste if treated with an alkali metal salt of a weak acid preferably in the presence of a solution of soap can be freed from impurities present and rendered suitable for satisfactory use in the manufacture of textile fabrics either alone or with cotton, silk, wool or the like. I also have discovered that by employing in such treating material an alkali metal base preferably the hydroxid, the filaments can not only be recovered in a form equal to the best product of the process in.

which such waste is produced but can be given 'the additional advantage of being crinkled whereby a fabric produced there from will have a resiliency or' life superior to fabrics woven from cellulose ester fila ments not so treated. By the employment of the alkali metal salt of a weak acid and an alkali metal base any cellulose ester filaments can be improved with respect to their resiliency and given a. crinkled form whereby ;cellulose'ester filaments closely resembling wool may beobtained. 1

In the preferred treatment of artificial silk waste in accordance with my process where an uncrinkled product is desired, I employ an alkali metal salt of a weak acid such for example assodium acetate, sodium sulfite, or sodium sulfide, and preferably the former, soap, preferably a neutral soap, and-water, in

the approximate proportions of one part'byweight of the alkali metal salt of a weak acid, 2- parts by weight of soap and- 97' parts by THEREOF.

Application filed September 1, 1928. Serial No. 133,079.

weightof water. If the soap is omitted the proportion of the. alkali metal salt to the water preferably one per cent of the former to 99 per cent of the latter. The artificial silk waste 1s immersed in this solution and subected to the action thereof at a temperature of approximately from 60 to 100 C. for an hour and a half or longer, until a satisfactory product is obtained. The proportions of the ma terials may be varied somewhat and the t me required to produce a satisfactory product depends in some degree upon the strength of'the solution and according to my experiments, to a greater extent upon the tempcrature at which the solution is maintained. If a the solution is maintained at about a boiling .temperatur e which is preferred, asatisfac tory product is usually obtained in an hour and a half. The soap may be omitted but in such case it has been found that prolonged washing of the waste filaments with the solution of thealkalimeta-l salt of a weak acid is required to obtain a satisfactory product, such washing frequently requiring from ten to fifteen hours or even longer in some cases. Where-a slightly crinkled product is desired the artificial silk waste is similarly treated but in such case the bath contains an addition to the ingredientsheretofore mentioned, about one per cent by wei ht of an alkali metal base preferably sodium hydroxid.

Where a more strongly crinkled product is desired the artificial silk waste is treated in the manner described but instead of employing one per cent by weight of the alkali metal gase I employ 2 per cent by weight of such ase.

By increasing the proportion of the alkali metal base the degree of crinkle in the product is increased. I have employed as high as 8 per cent by weight of the alkali metal base in the solution and obtained an extremely crinkled product.

In place of employing an alkali metal base in connection with the alkali metal salt of a weak-acid to effect .the crinkling action re ferred to I may with some measure of success employ correspondin alkaline earth metal bases but the results have notbeen as satisfactory as where alkali metal bases are used and the employment of. alkaline earth metal bases while contemplated as within the purview of my invention is not recommended for practical use.

, si'l'i enciy.

' applicable tothe treatment of merchantable cellulose-ester filaments as well as the waste filaments-to improve their quality and par- 1 ticularly to increase their resiliency and, if desired, to give them a noticeably crinkled appearance whereby the resulting filaments closely resemble wool.

In such use of the process the skeins of merchant-able denitrated cellulose or filaments derived from. other cellulose esters are preferably although .not necessarily first cut into desired short lengths to produce individual fibers of alength'to correspond with that of wool 'or cotton fibers. The preferred lengths of the fibers will depend in some measure upon-the treatment to which such fibers are to be subjected. If noticeably crinkled fibers resembling wool are to be obtained the filaments may advantage- 'ously' be cut into somewhat longer lengths than if uncrinkled or less crinkled fibers are to be produced. The cellulose filament skeins or the cut fibers thereof are then treated as described with the solution of an alkali metal salt of a weak acid to which may be added one.

.two or a higher per cent of the alkali metal base if crinkled fibers are to be obtained.

In treating merchantable artificial silk fibers the soap need not be employed but satisfactory results are obtainable if it is used in the preferred proportions in which it is employed in the combined reagentused in the treatment of Waste denitratcd .or other filaments derived from cellulose esters.

. Both the uncrinkled eind the crinkled prodrially improves the life of the fabric as I well as its appearance.

uct above referred to may be employed without the addition of other material in the production of textile fabrics or such product may be advantageouslyemployed wit cotton, silk or wool fiber. The employment of 10 or 15 per cent of such product with cotton mate- While I have described in detail the preferred practice of my process it is to be understood that my invention is not restricted thereto except as set'fo'rth inthe appended claims.

Icla'im: 1. The herein described process compris ing subjectingmellulose and cellulose esterfilaments to the action of anapproximately 1 per cent solution of an alkali metal salt of a weak acid in water.

2. The herein described process compris ng subjecting cellulose and cellulose ester filaing bath to the actionof a very ments'tothe action of an approximately 1 per cent solution of sodium'acet-ate in water.

3. The herein described process comprising subjecting cellulose ester filaments to the action of an aqueous solution of'an alkali metal salt of a weak acid and an alkali metal hydroxid containing approximately 1 per cent of the former and 1 to 8 per cent of the latter.

4. The herein described process comprising subjecting celluloseester filaments to the action of a dilute solution of an. alkali metal salt of a weak aci'd, an alkali metal hydroxid and soap.

' salt of a'weak acid, an alkali metal hydroxid and soap containing approximately 1 per cent of the alkali metal salt of the weak acid, 1 to 8 per. cent of the alkali metal hydroxid and 2 per cent of the soap..

7. The herein described process comprising subjecting completely formed and coagulated cellulose ester filaments subsequent to the coagulation of such filaments in the coagulating bath to the action of a very dilute solution of an alkali metal salt'of a weak acid.

8.1 The herein described process comprising subjecting completely formed and coagulated cellulose ester filaments subsequent to the coagulation of such filaments in the coagulatdilute solution of sodium acetate.

9. The herein described process comprising subjecting cellulose ester filaments to the ac "tion of a dilute solution of an alkali metal salt and an alkali metal h droxid, the hydroxid being present in sue solution in the proportions of approximately from 1 to 8%.

10. The herein described modified cellulose ester filaments comprising the reaction product of a coa'gulated cellulose ester in highly attenuated form and a very dilute solution of ab, alkali metal saltpf a weak acid, such filaform and a dilute solution of an alkali metal salt of a weak acid and an alkali metal hydroxid, the hydroxid being present in such solution in the proportions of approximately from 1 to 8 per cent and such filaments being crinkled and of a high degree of resiliency.

'In testimony whereof I afiix my signature.

HARRY P. BASSETT. 

